Removal of Heavy Metals from Aqueous Solutions Using Chitosan – Clay

Document Type : Research Paper



During the recent years, production of biological polymers has been considered as a tool for absorbing heavy metals. This is because of their non-toxicity properties and accessibility in the environment as well as their low price. Chitosan biological polymer has showed an extraordinary capability in coagulation and flocculation of suspended and colloidal particles, absorption of dissolved grease and oil and heavy metals. In this study, removing heavy metals (Al, Cd, Co, Cu, Fe and Pb) ions from aqueous solutions using chitosan – clay nanocomposites was investigated. After the addition of the absorbent into the reaction environment, parameters including absorption percentage of heavy metals (Al, Cd, Co, Cu, Fe, Pb) by chitosan-clay absorbent in acidities, contact time and the amount of absorbent matter were investigated. According to the results, by increasing pH of the solution, the adsorption of the metal ions was increased and the maximum adsorption occurred in pH 5 to 6. Absorption percentage had proportion with contact time: by increasing contact time, absorption percentage increased and reached equilibrium state after 3 hours. Also absorption percentage had proportion with the amount of the absorbent. By increasing the absorbent amount into the solution, metal absorption percentage was increased. So it can concluded that chitosan-clay nanocomposites has a good ability in removing heavy metals (Al, Cd, Co, Cu, Fe, Pb) from solution.

Keywords: Heavy metal, Nanocomposite, Chitosan, Clay, Adsorption, Aqueous solution